Chapter 2; Global Hazard Trends

Chapter 2; Global Hazard Trends

Magnitude and frequency.
Magnitude is the size of a natural hazard event and so represent the amount of work down (e.g. the energy given off during volcanic eruptions). Magnitude scales categorise events according to size/energy amd enable people to understand the processes and to model the likely impacts.Scales include:

hurricanes: Saffir - Simpson scale (1-5)

earthquakes: Richter scale (1 - 10)

tornadoes: TORRO

volcaninc eruptions: explosivity index

Frequency is how often of an event of a certain magnitude occurs. Low magnitude events are likely to be more frequent than high magnitude events which have low frequency.

Chapter 2; Global Hazard Trends

Global disaster trends: a summary
Naturual disasters are more common in countries with a low and medium level of development. Many of these countries are in tropical areas which have monsoon rainfall or hurricanes.
Disasters cause more death and disruption in poor countries, which lack the resources and funds to develop high-tech prevention and prediction systems.
Damage in absolute economic terms remains highest in high-income countries, but in relative terms it is much mroe devasting for poorer countries.